sysctl

SYSCTL(8)                    System Administration                   SYSCTL(8)



NAME
       sysctl - configure kernel parameters at runtime

SYNOPSIS
       sysctl [options] [variable[=value]] [...]
       sysctl -p [file or regexp] [...]

DESCRIPTION
       sysctl is used to modify kernel parameters at runtime.  The parameters
       available are those listed under /proc/sys/.  Procfs is required for
       sysctl support in Linux.  You can use sysctl to both read and write
       sysctl data.

PARAMETERS
       variable
              The name of a key to read from.  An example is kernel.ostype.
              The '/' separator is also accepted in place of a '.'.

       variable=value
              To set a key, use the form variable=value where variable is the
              key and value is the value to set it to.  If the value contains
              quotes or characters which are parsed by the shell, you may need
              to enclose the value in double quotes.

       -n, --values
              Use this option to disable printing of the key name when
              printing values.

       -e, --ignore
              Use this option to ignore errors about unknown keys.

       -N, --names
              Use this option to only print the names.  It may be useful with
              shells that have programmable completion.

       -q, --quiet
              Use this option to not display the values set to stdout.

       -w, --write
              Use this option when all arguments prescribe a key to be set.

       -p[FILE], --load[=FILE]
              Load in sysctl settings from the file specified or
              /etc/sysctl.conf if none given.  Specifying - as filename means
              reading data from standard input.  Using this option will mean
              arguments to sysctl are files, which are read in the order they
              are specified.  The file argument may be specified as regular
              expression.

       -a, --all
              Display all values currently available.

       --deprecated
              Include deprecated parameters to --all values listing.

       -b, --binary
              Print value without new line.

       --system
              Load settings from all system configuration files. Files are
              read from directories in the following list in given order from
              top to bottom.  Once a file of a given filename is loaded, any
              file of the same name in subsequent directories is ignored.
              /run/sysctl.d/*.conf
              /etc/sysctl.d/*.conf
              /usr/local/lib/sysctl.d/*.conf
              /usr/lib/sysctl.d/*.conf
              /lib/sysctl.d/*.conf
              /etc/sysctl.conf

       -r, --pattern pattern
              Only apply settings that match pattern.  The pattern uses
              extended regular expression syntax.

       -A     Alias of -a

       -d     Alias of -h

       -f     Alias of -p

       -X     Alias of -a

       -o     Does nothing, exists for BSD compatibility.

       -x     Does nothing, exists for BSD compatibility.

       -h, --help
              Display help text and exit.

       -V, --version
              Display version information and exit.

EXAMPLES
       /sbin/sysctl -a
       /sbin/sysctl -n kernel.hostname
       /sbin/sysctl -w kernel.domainname="example.com"
       /sbin/sysctl -p/etc/sysctl.conf
       /sbin/sysctl -a --pattern forward
       /sbin/sysctl -a --pattern forward$
       /sbin/sysctl -a --pattern 'net.ipv4.conf.(eth|wlan)0.arp'
       /sbin/sysctl --system --pattern '^net.ipv6'

DEPRECATED PARAMETERS
       The base_reachable_time and retrans_time are deprecated.  The sysctl
       command does not allow changing values of these parameters.  Users who
       insist to use deprecated kernel interfaces should push values to /proc
       file system by other means.  For example:

       echo 256 > /proc/sys/net/ipv6/neigh/eth0/base_reachable_time

FILES
       /proc/sys
       /etc/sysctl.conf

SEE ALSO
       sysctl.conf(5) regex(7)

AUTHOR
       George Staikos ⟨staikos@0wned.org⟩

REPORTING BUGS
       Please send bug reports to ⟨procps@freelists.org⟩



procps-ng                         2018-02-19                         SYSCTL(8)